Research Results
The contribution made by the Earthwatch project has meant that the Matura Beach leatherback colony has changed from a threatened colony in which hundreds of turtles were killed annually, to an apparently stable colony.
The results of research on leatherback sea turtle (Dermochelys coriacea) egg and hatchling production in 2009 showed an overall mean hatch success of 68% and average clutch size of 79 eggs, from which the researchers estimate that 380,184 eggs were deposited in 2009 (minimum possible number 293,125 eggs; maximum 467,243). If all nests survived, 240,793 hatchlings were produced. In 2010 researchers estimate that 807,913 ± 13,023 eggs were laid and the average hatching success was 52%.
The project has established a body mass index (or body mass condition) for leatherback turtles and in 2010, 47 leatherbacks were weighed. The mean body mass was 357 kg which was 29.3 kg higher than the mean BCI for all years the BCI has been recorded so far at Matura Beach. This data suggests that leatherbacks nesting in 2010 were successful in foraging in between the nesting seasons.
Results from a study of the impact of tourism on leatherback turtle nesting showed that the turtles reduce the duration of covering the nest slightly in the presence of tourists, but no other statistically significant effect of tourism on nesting behaviour was observed. The slight change in nest covering duration is not believed to be biologically detrimental and the researchers propose that Matura’s tourism programme does not negatively impact the behaviour of nesting leatherbacks.
Results from each season are reported to the Wildlife Section of the Forestry Division of the Government of Trinidad and Tobago. The Wildlife Section is the agency primarily responsible for managing and protecting the leatherback while it is in their waters and beaches.
Gilman, E., Gearhart, J., Price, B., Eckert, S., Milliken, H., Wang, J., Swimmer, Y., Shiode, D., Abe, O., Peckham, S.H., Chaloupka, M., Hall, M., Mangel, J., Alfaro-Shigueto, J., Dalzell, P., & Ishizaki, A. (2010) Mitigating sea turtle by-catch in coastal passive net fisheries. Fish and Fisheries, 11:57–88.
Crognale, M.A., Eckert, S.A., Levenson, D.H. & Harms, C.A. (2008) Leatherback sea turtle Dermochelys coriacea visual capacities and potential reduction of by-catch by pelagic longline fisheries. Endangered Species Research, 5(2-3):249-256.
Gearhart, J. & Eckert, S.A. (2007) Field tests to evaluate the target catch and bycatch reduction effectiveness of surface and mid-water drift gillnets in Trinidad. WIDECAST Information Document 2007-01. WIDECAST, Beaufort, North Carolina, USA